Seal face plate cooling

ABSTRACT

Aspects of the disclosure are directed to a sealing system for an engine having an axial centerline, comprising: a stationary carbon segment, and a seal plate that rotates when the engine is operated, where the seal plate includes an end face that is opposed to an interface between the carbon segment and the seal plate, and where the end face includes at least one groove that conveys a liquid cooling fluid.

This application claims priority to U.S. patent application Ser. No.15/294,923 filed Oct. 17, 2016, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

Gas turbine engines, such as those which power aircraft and industrialequipment, employ a compressor to compress air that is drawn into theengine and a turbine to capture energy associated with the combustion ofa fuel-air mixture. Seals are used in engines to isolate a fluid fromone or more areas/regions of the engine. For example, seals controlvarious parameters (e.g., temperature, pressure) within theareas/regions of the engine and ensure proper/efficient engine operationand stability.

Referring to FIG. 2A, a prior art sealing system 200 of an engine isshown. The system 200 is shown as including a bearing ring 206, adistribution feature 212, a seal plate 218, a carbon segment 224, and acarrier 230. The bearing ring 206 may be part of a larger bearingsystem/compartment that may support rotational hardware of the engine.The carrier 230 may support the carbon segment 224.

The seal plate 218 is configured to rotate, whereas the carbon segment224 is a stationary structure. In this respect, an interface 236 betweenthe seal plate 218 and the carbon segment 224 may be subject toheat/thermal loads that need to be managed. Opposed to, and axiallyforward of the interface 236 is a planar end face 252 of the seal plate218. The distribution feature 212 is used to convey oil to the sealplate 218 to cool the seal plate 218 in support of such thermalmanagement. The seal plate 218 includes radially-oriented holes 258 (seeFIG. 2B) that cool the seal plate 218 at discrete locations around thecircumference of the seal plate 218. The oil is ejected radiallyoutward/outboard from the seal plate 218 via the holes 258.

The holes 258 have a relatively small surface area for the cool oil todraw heat away from the seal plate 218. The oil passes through the holes258 quickly, with minimal time for the oil to cool the seal plate 218.Moreover, the use of the holes 258 provides for cooling at discretelocations on the seal plate 218. For example, and as best seen in FIG.2B, those portions 218 a of the seal plate 218 that are proximate to theholes 258 may tend to be cooler than those portions 218 b of the sealplate 218 that are further from the holes 258, such that the seal plate218 may be subject to waviness/lack of uniformity due to variations in adistance of locations/portions of the seal plate 218 relative to theholes 258.

Bearing compartment heat generation, which is influenced by oil flowrate, necessitates the use of fuel/oil and air/oil heat exchangers. Forexample, in order to cool the hardware as described above, relativelylarge oil flow rates may be needed in order to continue circulating cooloil to, e.g., the seal plate 218. The oil flow rates that are useddictate the sizes of an oil pump, tubes, and an oil tank. For example,the use of a large oil flow rate may result in the use of large oilpumps, tubes, and oil tanks. An increase in the size of the oil pumps,tubes, and oil tanks increases the weight of the engine, which has anegative impact on engine efficiency/performance.

BRIEF SUMMARY

The following presents a simplified summary in order to provide a basicunderstanding of some aspects of the disclosure. The summary is not anextensive overview of the disclosure. It is neither intended to identifykey or critical elements of the disclosure nor to delineate the scope ofthe disclosure. The following summary merely presents some concepts ofthe disclosure in a simplified form as a prelude to the descriptionbelow.

Aspects of the disclosure are directed to a sealing system for an enginehaving an axial centerline, comprising: a stationary carbon segment, anda seal plate that rotates when the engine is operated, where the sealplate includes an end face that is opposed to an interface between thecarbon segment and the seal plate, and where the end face includes atleast one groove that conveys a liquid cooling fluid. In someembodiments, the cooling fluid includes oil. In some embodiments, the atleast one groove includes a plurality of grooves formed between aplurality of fins, and where the grooves and fins are formed in analternating sequence. In some embodiments, each of the fins consumesapproximately fifty degrees of the circumference of the end face. Insome embodiments, the end face has a substantially constant groove widthto pitch ratio over a radial span of the end face. In some embodiments,the end face has a variable groove width to pitch ratio over a radialspan of the end face. In some embodiments, the groove width to pitchratio increases from an inner diameter of the end face towards an outerdiameter of the end face. In some embodiments, at least one groove isoriented in a first direction in traversing the groove from an innerdiameter of the end face towards an outer diameter of the end face, andwhere the seal plate rotates in a second direction when the engine isoperated. In some embodiments, the first direction is different from thesecond direction. In some embodiments, the system further comprises acarrier that supports the carbon segment, a bearing ring that supportsrotational hardware of the engine, the rotational hardware including theseal plate, and a distribution feature that provides the cooling fluidto the seal plate. In some embodiments, the at least one groove includesa plurality of grooves formed between a plurality of fins, and where atleast one of the fins is saw-tooth shaped. In some embodiments, the atleast one groove includes a plurality of grooves formed between aplurality of fins, and where at least one of the fins is L-shaped. Insome embodiments, the end face includes a tapered profile. In someembodiments, an outermost radial end of the end face is located axiallyforward of an innermost radial end of the end face. In some embodiments,the end face is located axially forward of the interface between thecarbon segment and the seal plate. In some embodiments, the at least onegroove includes a plurality of grooves formed between a plurality offins, and where the grooves and fins are continuous loops around acircumference of the end face.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example and not limitedin the accompanying figures in which like reference numerals indicatesimilar elements. The drawings are not necessarily drawn to scale unlessspecifically indicated otherwise.

FIG. 1 is a side cutaway illustration of a geared turbine engine.

FIG. 2A illustrates a prior art sealing system.

FIG. 2B illustrates a prior art seal plate of the system of FIG. 2A thatincorporates radially-oriented holes.

FIG. 3A illustrates a sealing system including a seal plate with an endface.

FIG. 3B illustrates an embodiment of an end face that incorporates oneor more fins and grooves with the fins and grooves having a constantgroove width to pitch ratio.

FIG. 3C illustrates an embodiment of an end face that incorporates oneor more fins and grooves with the fins and grooves having a variablegroove width to pitch ratio.

FIG. 3D illustrates an embodiment of an end face that includescontinuous loops/hoops of fins and grooves around a circumference of theend face.

FIG. 3E illustrates an embodiment of an end face that includessaw-toothed shaped fins.

FIG. 3F illustrates a closer, zoomed-in view of a portion of the endface of FIG. 3E.

FIG. 3G illustrates an embodiment of an end face that includes L-shapedfins.

FIG. 3H illustrates a closer, zoomed-in view of a portion of the endface of FIG. 3G.

FIG. 3I illustrates a closer, zoomed-in view of an end face thatincludes a taper/incline.

DETAILED DESCRIPTION

It is noted that various connections are set forth between elements inthe following description and in the drawings (the contents of which areincluded in this disclosure by way of reference). It is noted that theseconnections are general and, unless specified otherwise, may be director indirect and that this specification is not intended to be limitingin this respect. A coupling between two or more entities may refer to adirect connection or an indirect connection. An indirect connection mayincorporate one or more intervening entities.

In accordance with aspects of the disclosure, apparatuses, systems, andmethods are directed to sealing environments/applications. In someembodiments, an external surface/end face of a seal plate may includeone or more cooling fins and/or grooves. The use of the coolingfins/grooves may define a path for a cooling fluid (e.g., oil) totravel, where the use of the cooling fluid may remove heat from the sealplate.

Aspects of the disclosure may be applied in connection with a gasturbine engine. FIG. 1 is a side cutaway illustration of a gearedturbine engine 10. This turbine engine 10 extends along an axialcenterline 12 between an upstream airflow inlet 14 and a downstreamairflow exhaust 16. The turbine engine 10 includes a fan section 18, acompressor section 19, a combustor section 20 and a turbine section 21.The compressor section 19 includes a low pressure compressor (LPC)section 19A and a high pressure compressor (HPC) section 19B. Theturbine section 21 includes a high pressure turbine (HPT) section 21Aand a low pressure turbine (LPT) section 21B.

The engine sections 18-21 are arranged sequentially along the centerline12 within an engine housing 22. Each of the engine sections 18-19B, 21Aand 21B includes a respective rotor 24-28. Each of these rotors 24-28includes a plurality of rotor blades arranged circumferentially aroundand connected to one or more respective rotor disks. The rotor blades,for example, may be formed integral with or mechanically fastened,welded, brazed, adhered and/or otherwise attached to the respectiverotor disk(s).

The fan rotor 24 is connected to a gear train 30, for example, through afan shaft 32. The gear train 30 and the LPC rotor 25 are connected toand driven by the LPT rotor 28 through a low speed shaft 33. The HPCrotor 26 is connected to and driven by the HPT rotor 27 through a highspeed shaft 34. The shafts 32-34 are rotatably supported by a pluralityof bearings 36; e.g., rolling element and/or thrust bearings. Each ofthese bearings 36 is connected to the engine housing 22 by at least onestationary structure such as, for example, an annular support strut.

During operation, air enters the turbine engine 10 through the airflowinlet 14, and is directed through the fan section 18 and into a core gaspath 38 and a bypass gas path 40. The air within the core gas path 38may be referred to as “core air”. The air within the bypass gas path 40may be referred to as “bypass air”. The core air is directed through theengine sections 19-21, and exits the turbine engine 10 through theairflow exhaust 16 to provide forward engine thrust. Within thecombustor section 20, fuel is injected into a combustion chamber 42 andmixed with compressed core air. This fuel-core air mixture is ignited topower the turbine engine 10. The bypass air is directed through thebypass gas path 40 and out of the turbine engine 10 through a bypassnozzle 44 to provide additional forward engine thrust. This additionalforward engine thrust may account for a majority (e.g., more than 70percent) of total engine thrust. Alternatively, at least some of thebypass air may be directed out of the turbine engine 10 through a thrustreverser to provide reverse engine thrust.

FIG. 1 represents one possible configuration for an engine 10. Aspectsof the disclosure may be applied in connection with other environments,including additional configurations for gas turbine engines. Aspects ofthe disclosure may be applied in connection with non-geared engines.

Referring to FIG. 3A, a sealing system 300 is shown. The system 300 mayinclude a seal plate 318. The seal plate 318 may interface to the carbonsegment 224 at an interface 336. The interface 336 may tend to get hot,such that a cooling fluid (e.g., oil) may be supplied to the seal plate318 to remove some of the heat from the seal plate 318. For example, theseal plate 318 may receive a cooling fluid from the distribution feature212.

As shown in FIG. 3A, a (forward) surface/end face 342 of the seal plate318 may include features that assist in the cooling/removal of heat fromthe seal plate 318 as described further below. The end face 342 and theinterface 336 are on opposite sides of the seal plate 318.

Additionally, the end face 342 is shown in FIG. 3A as including atapered profile, where the outermost radial end 343 a of the end face342 is located axially forward of the innermost radial end 343 b of theend face 342. In some embodiments, such a taper might not be includedsuch that the outermost radial end 343 a of the end face 342 may belocated in substantially the same axial plane/station as the innermostradial end 343 b of the end face 342. In some embodiments, the taper mayprogress in a direction that is opposite from what is shown in FIG. 3A;for example, the outermost radial end 343 a of the end face 342 may belocated axially aft of the innermost radial end 343 b of the end face342 in some embodiments. Referring to FIG. 3I, a particular angle/degreeof taper that may be used is shown, where relative to an axialstation/plane 344 a portion of an end face 362 (where the end face 362may correspond to the end face 342 of FIG. 3A) is shown as beinginclined by an amount denoted by an angle 346. The inclination may helpto ensure that cooling fluid does not separate from the end face 342/362before reaching an outer diameter of the end face 342/362, thuspromoting heat transfer. With such an arrangement, a width of the sealplate measured along the axial centerline between the end faces of theseal plate may increase as the seal plate extends radially away from theaxial centerline.

An end face 352 (where the end face 352 may correspond to the end face342 of FIG. 3A) of an exemplary embodiment is shown in FIG. 3B. Inparticular, the end face 352 of FIG. 3B is shown as including one ormore ridges/fins 358 arranged in an alternating sequence with respect toone or more recesses/grooves 360 that may be used in the conveyance of acooling fluid. The grooves 360 may be obtained by, e.g.,machining/milling the seal plate 318 (see FIG. 3A). Other techniques,such as for example chemical etching, electrical discharge machining(EDM)/additive manufacturing/machining, etc., may be used to manufacturethe end face 352.

In contrast to the use of the radial holes 258 of FIG. 2B, the use ofthe fins 358 and grooves 360 may tend to pool the cooling fluid in thegrooves 360 and may serve to extend the time/distance that the coolingfluid remains engaged with the seal plate 318 before being ejected fromthe seal plate 318 (where such ejection may be based on a centrifugalforce imparted on the cooling fluid). Additionally, a channeling of thecooling fluid in the grooves 360 may provide for an increased surfacearea for the cooling fluid to contact the seal plate 318. In thisrespect, for a given set of an oil pump, tubes, and oil tank, thearrangement of FIGS. 3A-3B may provide enhanced coolingefficiency/performance relative to the arrangement shown in FIGS. 2A-2B.Additionally, the use of the fins 358 and grooves 360 as shown in FIG.3B may provide for cooling over the entire circumference of the sealplate 318 (as opposed to just at discrete, circumferential locationsthat are proximate the radial holes 258 as in FIG. 2B).

While the embodiment shown in FIG. 3B includes multiple fins 358 andgrooves 360 (also referred to herein as an end face 352 includingmultiple starts) with each fin 358 consuming approximately fifty degreesof the overall circumference of the end face 352, in some embodiments asingle fin 358 (or analogously, groove 360) may be used (where thatsingle fin 358 may consume the three-hundred sixty degree circumferenceof the end face 352). More generally, any number of fins 358 or grooves360 may be included in a given embodiment.

As shown in FIG. 3B, the fins 358 and the grooves 360 may be oriented ina clockwise direction in terms of travel/progression along a given fin358/groove 360 from the inner diameter of the end face 352 to the outerdiameter of the end face 352. In some embodiments, the fins 358 and thegrooves 360 may be oriented in a counterclockwise direction in terms oftravel/progression along a fin 358/groove 360 from the inner diameter ofthe end face 352 to the outer diameter of the end face 352.

In some embodiments, the particular orientation (e.g., clockwise orcounterclockwise as described above) for the fins 358/grooves 360 may beselected to be opposite to the direction of the rotation of the sealplate 318. For example, from the perspective of looking forward-to-aftas shown in FIG. 3B, the clockwise orientation (progressing from theinner diameter to the outer diameter of the end face 352) of the fins358/grooves 360 may coincide with a counterclockwise rotation of the endface 352/seal plate 318 when the associated engine is operated. Havingan orientation of the fins 358/grooves 360 different from a direction ofrotation of the end face 352/seal plate 318 may serve to entrap/entrainthe cooling fluid for a longer period of time than if the orientation ofthe fins 358/grooves 360 was in the same direction as the direction ofrotation of the end face 352/seal plate 318, thereby enhancing thecooling efficiency/performance.

As shown in FIG. 3B, at the inner diameter of the end face 352 the fins358 may have a circumferential width as denoted by arrow 368 and thegrooves 360 may have a circumferential width as denoted by arrow 370.Similarly, at the outer diameter of the end face 352 the fins 358 mayhave a circumferential width as denoted by arrow 378 and the grooves 360may have a circumferential width as denoted by arrow 380.

As used herein, the term “pitch” may refer to the distance of arepeatable pattern. For example, in the context of the widths 368 and370, the summation of the widths 368 and 370 represents the pitch asmeasured at the inner diameter of the end face 352 in FIG. 3B.Similarly, the summation of the widths 378 and 380 represents the pitchas measured at the outer diameter of the end face 352 in FIG. 3B.

In FIG. 3B, a constant “groove width to pitch ratio” is shown over theradial span of the end face 352. For example, the width 370 divided bythe summation of the widths 370 and 368 is the same as the width 380divided by the summation of the widths 380 and 378. In the embodimentshown in FIG. 3B, the groove width to pitch ratio may be approximatelyequal to 50%.

In contrast to the constant groove width to pitch ratio of the end face352 of FIG. 3B, FIG. 3C illustrates an embodiment of an end face 352′where the groove width to pitch ratio may vary over a radial span of theend face 352′. For example, in FIG. 3C the fins 358 may have acircumferential width as denoted by arrow 368′ and the grooves 360 mayhave a circumferential width as denoted by arrow 370′ at the innerdiameter of the end face 352′. At the outer diameter of the end face352′, the fins 358 may have a circumferential width as denoted by arrow378′ and the grooves 360 may have a circumferential width as denoted byarrow 380′.

The groove width to pitch ratio as measured at the inner diameter of theend face 352′ may be approximately the same as measured at the innerdiameter of the end face 352 of FIG. 2B (e.g., the groove width to pitchratio as measured at the inner diameter of the end face 352′ may beapproximately equal to 50%). However, the groove width to pitch ratio asmeasured at the outer diameter of the end face 352′ may be approximatelyequal to 75%. In the embodiment of FIG. 3C, the groove width to pitchratio is thus seen as increasing in progressing from the inner diameterof the end face 352′ towards the outer diameter of the end face 352′ dueto, e.g., a widening of the grooves 360 in progressing in a radiallyoutward direction in FIG. 3C.

FIG. 3D illustrates an embodiment of an end face 352″. In contrast tothe embodiments shown in FIGS. 3B-3C, the end face 352″ is shown asincluding continuous loops of fins 358 and grooves 360 around thecircumference of the end face 352″. The end face 352″ may be easier tomanufacture than the end faces 352 or 352′ of FIGS. 3B and 3C,respectively, due to the continuous nature of the fins 358 and thegrooves 360.

FIG. 3E illustrates an embodiment of an end face 352′″. Much like theend face 352″ of FIG. 3D, the end face 352′″ of FIG. 3E may includecontinuous loops of fins 358 and grooves 360 around the circumference ofthe end face 352′″. As reflected in the boxed portion 352 e of FIG. 3E(which portion 352 e is depicted in a closer, zoomed-in view in FIG.3F), the fins 358 of the end face 352′″ of FIG. 3E may be saw-toothed inshape. The use of the saw-toothed shape for the fins 358 may assist infurther entraining/entrapping the cooling fluid in the grooves 360(relative to, e.g., the embodiments of FIGS. 3B-3D), thereby furtherenhancing the cooling efficiency/performance.

FIG. 3G illustrates an embodiment of an end face 352″″. Much like theend faces of FIGS. 3D and 3E, the end face 352″″ of FIG. 3G may includecontinuous loops of fins 358 and grooves 360 around the circumference ofthe end face 352″″. As reflected in the boxed portion 352 g of FIG. 3G(which portion 352 g is depicted in a closer, zoomed-in view in FIG.3H), the fins 358 of the end face 352″″ of FIG. 3G may be L-shaped. Theuse of the L-shaped fins 358 may assist in further entraining/entrappingthe cooling fluid in the grooves 360 (relative to, e.g., the saw-toothedshape of FIGS. 3E-3F), thereby further enhancing the coolingefficiency/performance.

As would be appreciated by one of skill in the art, the particulararrangement/parameters (e.g., count of fins or grooves, pitch/width,orientation/direction of the fins or grooves, taper/inclination, etc.)for an end face may be determined in accordance with simulation,testing, analysis, etc. For example, a finite element thermal analysismay be performed to determine and select the particular parameters for agiven set of application requirements or performance metrics.

Technical effects and benefits of this disclosure include anaxisymmetric (e.g., circumferential and radial) cooling profile for anend face of a seal plate that reduces/eliminates seal plate waviness. Agreater surface area coupled with longer dwell times improves coolingeffectiveness/efficiency of a cooling fluid (e.g., a lower oil flow ratemay be used for the same level/degree of cooling in accordance withaspects of this disclosure). One or more fins or grooves may be includedin an end face. The grooves may be milled into the seal plate; such atechnique may be inexpensive in terms of operator cost and may imposeminimal stress on the seal plate. The particular parameters that areused for an end face may be at least partially based on a trade-offbetween manufacturing complexity/simplicity on one hand and coolingrequirements/effectiveness/efficiency on the other hand.

Aspects of the disclosure have been described in terms of illustrativeembodiments thereof. Numerous other embodiments, modifications, andvariations within the scope and spirit of the appended claims will occurto persons of ordinary skill in the art from a review of thisdisclosure. For example, one of ordinary skill in the art willappreciate that the steps described in conjunction with the illustrativefigures may be performed in other than the recited order, and that oneor more steps illustrated may be optional in accordance with aspects ofthe disclosure. One or more features described in connection with afirst embodiment may be combined with one or more features of one ormore additional embodiments.

What is claimed is:
 1. A sealing system for an engine having an axialcenterline, comprising: a stationary carbon seal element; and a sealplate configured to rotate about the axial centerline, the seal platecomprising a first end face and a second end face opposite the first endface along the axial centerline, wherein a width of the seal platemeasured along the axial centerline between the first end face and thesecond end face increases as the seal plate extends radially away fromthe axial centerline; the first end face is configured to interface withthe stationary carbon element; and the second end face configured withone or more grooves for conveying a liquid.
 2. The sealing system ofclaim 1, wherein a first of the one or more grooves is a continuousgroove that extends circumferentially about the axial centerline.
 3. Thesealing system of claim 1, wherein a first of the one or more grooveshas a rectangular cross-sectional geometry.
 4. The sealing system ofclaim 1, wherein a first of the one or more grooves has an L-shapedcross-sectional geometry.
 5. The sealing system of claim 1, wherein theone or more grooves are defined by a plurality of fins carried by thesecond end face.
 6. The sealing system of claim 5, wherein a first ofthe plurality of fins has a rectangular cross-sectional geometry.
 7. Thesealing system of claim 5, wherein a first of the plurality of fins hasa triangular cross-sectional geometry.
 8. The sealing system of claim 5,wherein a first of the plurality of fins has an L-shaped cross-sectionalgeometry.
 9. The sealing system of claim 1, further comprising: acarrier configured to support the stationary carbon element; a bearingring configured to support rotational hardware of the engine, therotational hardware including the seal plate; and a distribution featurethat provides the liquid to at least one of the one or more grooves. 10.The sealing system of claim 1, wherein a first of the plurality of oneor more grooves is formed between a first fin of the second end face anda second fin of the second end face; and the first fin has saw-toothshaped.
 11. The sealing system of claim 1, wherein an outermost radialend of the second end face is located axially forward of an innermostradial end of the second end face.
 12. A sealing system for an enginehaving an axial centerline, comprising: a stationary carbon sealelement; and a seal plate configured to rotate about the axialcenterline, the seal plate comprising a first end face and a second endface opposite the first end face along the axial centerline, wherein awidth of the seal plate measured along the axial centerline between thefirst end face and the second end face increases as the seal plateextends radially away from the axial centerline; the first end face isconfigured to interface with the stationary carbon element; and thesecond end face configured with one or more continuous grooves extendingcircumferentially about the axial centerline.
 13. The sealing system ofclaim 12, wherein a first of the one or more continuous grooves has arectangular cross-sectional geometry.
 14. The sealing system of claim12, wherein a first of the one or more continuous grooves has anL-shaped cross-sectional geometry.
 15. The sealing system of claim 12,wherein the one or more continuous grooves are defined by a plurality offins carried by the second end face.
 16. The sealing system of claim 15,wherein a first of the plurality of fins has a rectangularcross-sectional geometry.
 17. The sealing system of claim 15, wherein afirst of the plurality of fins has a triangular cross-sectionalgeometry.
 18. The sealing system of claim 15, wherein a first of theplurality of fins has an L-shaped cross-sectional geometry.
 19. Thesealing system of claim 12, wherein an outermost radial end of thesecond end face is located axially forward of an innermost radial end ofthe second end face.
 20. A sealing system for an engine having an axialcenterline, comprising: a stationary carbon segment; and a seal platethat rotates when the engine is operated; wherein the seal plateincludes an end face that is opposed to an interface between the carbonsegment and the seal plate; wherein the end face includes a groove thatconveys a liquid cooling fluid; wherein the groove starts at arespective first circumferential location of the end face at an innerdiameter of the end face and ends at a respective second circumferentiallocation of the end face at an outer diameter of the end face, the firstand second circumferential locations being different circumferentiallocations; wherein the end face includes a fin adjacent the groove;wherein the end face has a non-constant groove width to pitch ratio overa radial span of the end face; and wherein the groove width to pitchratio increases from the inner diameter of the end face towards theouter diameter of the end face.